JP5533344B2 - Driving force distribution device - Google Patents

Description

  The present invention relates to a driving force distribution device useful as a transfer for a four-wheel drive vehicle, and more particularly to a friction transmission type driving force distribution device.

As a friction transmission type driving force distribution device, a device as described in Patent Document 1, for example, has been known.
The driving force distribution device described in this document includes a first roller mechanically coupled to a main drive wheel and a second roller mechanically coupled to a slave drive wheel. The first roller and the second roller By causing the rollers to make frictional contact with each other on the outer peripheral surfaces of the rollers, a part of the torque to the main drive wheels can be distributed to the driven wheels and output.

  In such a driving force distribution device, by adjusting the radial pressing force between the first roller and the second roller, the torque transmission capacity between these rollers, and accordingly, the driving force distribution between the main driving wheel and the sub driving wheel Can be controlled.

  As a mechanism for performing this driving force distribution control, Patent Document 1 discloses that the second roller is displaced in the radial direction relative to the first roller by turning the rotation shaft of the second roller around an eccentric axis with a motor or the like. Thus, a configuration has been proposed in which the radial pressing force between the first roller and the second roller, that is, the distribution of the driving force between the main driving wheel and the sub driving wheel can be controlled.

JP 2009-173261 A (FIG. 5)

  However, in such a conventional driving force distribution device, the radial pressing force between the first roller and the second roller is set to the command value by the motor or the like, and the target driving force distribution between the main and slave driving wheels is distributed. After the above is achieved, the motor or the like needs to continue to operate so as to keep the inter-roller radial pressing force at the unchanged command value while the inter-roller radial pressing force command value remains unchanged.

  This means that as long as it is necessary to distribute the driving force to the driven wheels, the motor or the like continuously applies the radial pressing force between the rollers even while the radial pressing force command value between the rollers is a constant value. This means that electric power for maintaining a constant command value that does not change is consumed, resulting in a problem of increased energy loss.

  In the present invention, the time required to keep the energy consumed for the control as long as possible is as long as possible within a range that does not adversely affect the radial pressing force control between the rollers (the driving force distribution control between the main and slave driving wheels). Thus, an object of the present invention is to propose a driving force distribution device that can solve the above-described problem that the energy loss increases.

For this purpose, the driving force distribution device according to the present invention is configured as follows.
First of all, to explain the premise driving force distribution device,
A first roller mechanically coupled to the main drive wheel;
A second roller that is mechanically coupled to the driven wheel and distributes the driving force to the driven wheel by frictional contact with the first roller;
The distribution of the driving force between the main driving wheel and the sub driving wheel is controlled by adjusting the radial pressing force between the first roller and the second roller.

The present invention provides the following improvements to such a driving force distribution device.
First, an operating force from a roller-to-roller radial pressing force generation source that responds to the radial-direction pressing force command value between the rollers is adjusted so as to adjust the radial-direction pressing force between the first roller and the second roller to a command value. An irreversible transmission mechanism is provided to transmit under irreversible, and the inter-roller radial pressing force is generated by the non-operation of the inter-roller radial pressing force generation source while the inter-roller radial pressing force command value remains unchanged. The command value can be held.

Furthermore, there is provided driving state determination means for determining whether the driving state requires high-accuracy driving force distribution control between the main driving wheel and the slave driving wheel or the driving state that does not require high-precision driving force distribution control. The operation state determination means is
In the case of the first invention of claim 1, high-precision driving force distribution control between the main drive wheel and the sub drive wheel is required with at least one of the main drive wheel and the sub drive wheel being steered. It is determined that the main driving wheel and the sub driving wheel are not steered, and that the driving state is not required for high-precision driving force distribution control between the main driving wheel and the sub driving wheel. And
In the case of the second invention of claim 2, in a state where at least one of the main driving wheel and the sub driving wheel is subjected to the brake lock prevention control, the highly accurate driving force distribution control between the main driving wheel and the sub driving wheel is performed. A driving state in which it is determined that the driving state is required, and the main driving wheel and the sub driving wheel are not subjected to brake lock prevention control, and high-precision driving force distribution control between the main driving wheel and the sub driving wheel is not required. To be judged,
In the case of the third invention of claim 3, with at least one of the main driving wheel and the sub driving wheel being subjected to braking / driving force control for behavior control of the vehicle, high accuracy between the main driving wheel and the sub driving wheel is obtained. In which the driving force distribution control is required, and the main driving wheel and the sub driving wheel are not controlled by the braking / driving force for controlling the behavior of the vehicle. It is assumed that it is determined that the driving state does not require high-precision driving force distribution control.
And, when it is determined by the operating state determination means that the driving state is not required highly accurate driving force distribution control, compared with the case where it is an operating state that requires highly accurate driving force distribution control, There is provided command value resolution switching means that contributes to the operation control of the inter-roller radial pressing force generation source with a low resolution radial inter-roller pressing force command value having a long invariable time.

According to the driving force distribution device of the first to third inventions, the following operational effects can be obtained.
In other words, by installing the irreversible transmission mechanism described above, the inter-roller radial pressing force is maintained at the command value even when the inter-roller radial pressing force command value remains unchanged, even when the inter-roller radial pressing force generation source is inactive. It will be possible.
As described above, the time during which the radial pressing force generation source between the rollers can be kept inactive during the driving force distribution control provides a time for setting the energy consumed for the driving force distribution control to zero. Thus, energy loss during the driving force distribution control can be suppressed.

  However, the suppression of the energy loss is realized if the time during which the radial pressing force generation source between the rollers can be kept inactive, that is, the time during which the radial pressing force command value between the rollers is an invariable constant value is not long. I can't.

By the way, in the first to third inventions, in the operation state in which high-precision driving force distribution control is required as the inter-roller radial pressing force command value, in the operation state in which high-precision driving force distribution control is not required, In order to control the radial pressing force generation source between the rollers using the low-resolution radial pressing force command value between the rollers, which has a long time that remains unchanged compared to a certain case,
When the driving state does not require high-accuracy driving force distribution control, the time during which the radial pressing force command value between rollers does not change, that is, the non-operation of the radial pressing force generation source between rollers causes It takes longer to keep energy consumption at 0,
The problem that the energy loss during the driving force distribution control becomes large can be solved.

In addition, when using the low-resolution radial pressing force command value between the rollers, naturally, the driving force distribution control also becomes low accuracy.
If the driving state does not require high-accuracy driving force distribution control, there is no practical problem even if the driving force distribution control is low accuracy. There is no hindrance.

  In addition, when the driving state requires high-precision driving force distribution control, the above-mentioned low-resolution radial pressing force command value between rollers is not used, so high-precision driving force distribution control is sacrificed. It can be carried out as planned without having to.

Therefore, according to the first to third inventions, the time during which the energy consumed for the control can be set to 0 is as long as possible within a range that does not adversely affect the driving force distribution control.
The above-mentioned problem that the energy loss becomes large can be surely solved by suppressing the energy loss at the time of the control while preventing the driving force distribution control from being affected.

1 is a schematic plan view showing a power train of a four-wheel drive vehicle including a driving force distribution device according to a first embodiment of the present invention as viewed from above the vehicle. FIG. 2 is a longitudinal side view of the driving force distribution device in FIG. FIG. 3 is a longitudinal front view showing a crankshaft used in the driving force distribution device shown in FIG. FIG. 3 is an end view showing the torque diode in the driving force distribution device of FIG. 2 when viewed from the output shaft side in the axial direction. FIG. 5 is a longitudinal side view of the torque diode shown in FIG. FIGS. 4A and 5B are explanatory diagrams of the operation of the torque diode, and FIG. 4A is an explanatory diagram for explaining the irreversible transmission operation of the torque diode in a state where there is no input torque for driving force distribution control. FIG. 6 is an explanatory diagram for explaining a state immediately after the input torque for driving force distribution control is generated, and (c) illustrates a state when the input torque for driving force distribution control starts to be transmitted to the output shaft. It is explanatory drawing for doing. FIG. 3 is a control system diagram showing a driving force distribution control system by a roller radial pressing force control motor in FIG. FIG. 8 is a flowchart showing a driving force distribution control program executed by the transfer controller in FIG. Fig. 8 shows a characteristic diagram of the map used to determine the command torque capacity in the control program of Fig. 8, and (a) shows the characteristics of low-resolution command torque capacity used during operation that does not require high-accuracy driving force distribution control. The diagram (b) is a characteristic diagram of the command torque capacity with high resolution used during the operation that requires high-precision driving force distribution control. FIG. 6 is a characteristic diagram of low-resolution command torque capacity used during driving force distribution control of the driving force distribution device according to the second embodiment of the present invention. FIG. 10 is a time-series change characteristic diagram of a low-resolution command torque capacity at the time of driving force distribution control of the driving force distribution device according to the third embodiment of the present invention. FIG. 10 is a time-series change characteristic diagram of low-resolution command torque capacity at the time of driving force distribution control of the driving force distribution device according to the fourth embodiment of the present invention. FIG. 10 is a time-series change characteristic diagram of a low-resolution command torque capacity during driving force distribution control of the driving force distribution device according to the fifth embodiment of the present invention. FIG. 10 is a time-series change characteristic diagram of a low-resolution command torque capacity during driving force distribution control of the driving force distribution device according to the sixth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail based on the illustrated examples.
<First embodiment>
FIG. 1 is a schematic plan view showing a power train of a four-wheel drive vehicle provided with a driving force distribution device 1 according to a first embodiment of the present invention as a transfer as viewed from above the vehicle.

The four-wheel drive vehicle in FIG. 1 is a rear-wheel drive vehicle in which rotation from the engine 2 is transmitted to the left and right rear wheels 6L and 6R through the rear propeller shaft 4 and the rear final drive unit 5 after being shifted by the transmission 3. As a base vehicle,
Part of the torque to the left and right rear wheels (main drive wheels) 6L and 6R is transmitted to the left and right front wheels (secondary drive wheels) 7L and 7R through the front propeller shaft 7 and the front final drive unit 8 sequentially by the driving force distribution device 1. By doing so, the vehicle can be driven by four-wheel drive.

  As described above, the driving force distribution device 1 distributes and outputs a part of the torque to the left and right rear wheels (main driving wheels) 6L and 6R to the left and right front wheels (secondary driving wheels) 7L and 7R. (Main drive wheels) 6L, 6R and left and right front wheels (secondary drive wheels) 9L, 9R to determine the drive force distribution ratio. In this embodiment, this drive force distribution device 1 is as shown in FIG. Configure.

In FIG. 2, reference numeral 11 denotes a housing, and an input shaft 12 and an output shaft 13 are installed in the housing 11 so as to be inclined with respect to each other so that the respective rotation axes O ₁ and O ₂ cross each other.
The input shaft 12 is rotatably supported with respect to the housing 11 by ball bearings 14 and 15 at both ends thereof.
Both ends of the input shaft 12 are protruded from the housing 11 under liquid-tight sealing by seal rings 25 and 26, respectively.
2, the left end of the input shaft 12 is coupled to the output shaft of the transmission 3 (see FIG. 1), and the right end is coupled to the rear final drive unit 5 via the rear propeller shaft 4 (see FIG. 1).

Arranged near the both ends of the input shaft 12 and the output shaft 13, respectively, a pair of bearing supports 16, 17 are installed between the input / output shafts 12, 13, and the bearing supports 16, 17 are arranged in the middle of each bolt. 18 and 19 are attached to the axially opposed inner walls of the housing 11.
Roller bearings 21 and 22 are interposed between the bearing supports 16 and 17 and the input shaft 12 so that the input shaft 12 can be rotated with respect to the bearing supports 16 and 17. However, the input shaft 12 is rotatably supported in the housing 11.

A first roller 31 is integrally formed coaxially at an intermediate position in the axial direction of the input shaft 12 between the bearing supports 16 and 17 (between the roller bearings 21 and 22) and arranged so as to be in frictional contact with the first roller 31. The second roller 32 is integrally formed coaxially at a position in the middle of the output shaft 13 in the axial direction.
The outer peripheral surfaces of the first roller 31 and the second roller 32 are conical tapered surfaces that can come into line contact with each other even when the input shaft 12 and the output shaft 13 are inclined as described above.

The output shaft 13 is rotatably supported in the housing 11 via the bearing supports 16 and 17 by rotatably supporting the bearing supports 16 and 17 near both ends thereof.
Thus, when the output shaft 13 is rotatably supported on the bearing supports 16 and 17, the following support structure is used.

A hollow outer shaft type crankshaft 51L, 51R is loosely fitted between the output shaft 13 and the bearing supports 16, 17 through which the output shaft 13 passes.
The crankshaft 51L and the output shaft 13 protrude from the housing 11 at the left end in FIG. 2, respectively, and the seal ring 27 is interposed between the housing 11 and the crankshaft 51L at the protruding portion, and the seal between the crankshaft 51L and the output shaft 13 is sealed. The crankshaft 51L protruding from the housing 11 and the protruding portion of the output shaft 13 are liquid-tightly sealed with the ring 28 interposed.

  In FIG. 2, the left end of the output shaft 13 discharged from the housing 11 is coupled to the left and right front wheels 9L and 9R via the front propeller shaft 7 (see FIG. 1) and the front final drive unit 8.

Roller bearings 52L and 52R are interposed between the center holes 51La and 51Ra (radius Ri) of the crankshafts 51L and 51R and the corresponding ends of the output shaft 13, and the output shaft 13 is connected to the center holes of the crankshafts 51L and 51R. 51La, within 51Ra, supports that can freely rotate around these central axis O _2.

As clearly shown in FIG. 3, the crankshafts 51L and 51R have outer peripheral portions 51Lb and 51Rb (radius Ro) that are eccentric with respect to the central holes 51La and 51Ra (central axis O ₂ ), and the eccentric outer peripheral portions 51Lb and 51Rb The central axis O ₃ is offset from the axial line O ₂ of the central holes 51La and 51Ra by an eccentricity ε between them.
The eccentric outer peripheral portions 51Lb and 51Rb of the crankshafts 51L and 51R are rotatably supported in bearing supports 16 and 17 on the corresponding side via roller bearings 53L and 53R, respectively.
At this time, the crankshafts 51L and 51R, together with the second roller 32, are positioned in the axial direction by the thrust bearings 54L and 54R.

Ring gears 51Lc and 51Rc having the same specifications are integrally provided at adjacent ends of the crankshafts 51L and 51R facing each other.
The ring gears 51Lc and 51Rc are respectively engaged with crankshaft drive pinions 55L and 55R having the same specifications, and the crankshaft drive pinions 55L and 55R are coupled to a common pinion shaft 56.

  As described above, when the crankshaft drive pinions 55L and 55R are engaged with the ring gears 51Lc and 51Rc, the crankshafts 51L and 51R are aligned with each other in the circumferential direction so that the eccentric outer peripheral portions 51Lb and 51Rb are aligned in the circumferential direction. In the state where the rotation position is established, the crankshaft drive pinions 55L and 55R are engaged with the ring gears 51Lc and 51Rc.

Both ends of the pinion shaft 56 are rotatably supported with respect to the housing 11 by bearings 56a and 56b.
The right end of the pinion shaft 56 on the right side of FIG. 2 passes through the housing 11 and protrudes therefrom,
The exposed end of the pinion shaft 56 is an output of a roller-to-roller radial pressing force control motor 58 (a roller-to-roller radial pressing force generation source) via a reduction gear box 57 including a small-diameter input gear 57a and a large-diameter output gear 57b. Drive coupled to shaft 58a.

Therefore, when the rotational position of the crankshafts 51L, 51R is controlled by the inter-roller radial pressing force control motor 58 via the pinions 55L, 55R and the ring gears 51Lc, 51Rc,
The rotation axis O ₂ of the output shaft 13 and the second roller 32 pivots around the central axis O ₃ along a locus circle indicated by a broken line in FIG. 3, and the first axis is changed by changing the inter-axis distance between the rollers 31 and 32. The radial pressing force of the second roller 32 against the roller 31 can be arbitrarily controlled.

  Incidentally, in this embodiment, in particular, the input shaft 59 of the reduction gear box 57 to which the small-diameter input gear 57a is coupled and the output shaft 58a of the inter-roller radial direction pressing force control motor 58 are not directly connected. The input shaft 59 of the reduction gear box 57 and the output shaft 58a of the inter-roller radial pressing force control motor 58 are coupled to each other through the torque diode 61.

<Torque diode>
The torque diode 61 decelerates from the inter-roller radial pressing force control motor 58 (output shaft 58a) regardless of the rotational operation force from the inter-roller radial pressing force control motor 58 (output shaft 58a). The transmission to the gear box 57 (input shaft 59) is freely performed, but the reverse transmission from the reduction gear box 57 (input shaft 59) to the roller radial pressing force control motor 58 (output shaft 58a) is decelerated. This is used for an irreversible transmission mechanism that is not operated by the two-way rotation lock of the gear box 57 (input shaft 59), and has a configuration as described below with reference to FIGS.

That is, the torque diode 61 attaches and fixes the cylindrical case 62 to the housing 57c of the reduction gear box 57 as shown in FIG.
As shown in FIGS. 4 and 5, the input shaft 63 from one side in the axial direction of the fixed case 62 and the output shaft 64 from the other side in the axial direction are arranged so as to be coaxial with each other and enter the fixed case 62. .
The input shaft 63 is rotatably supported with respect to the fixed case 62 by a bearing 65, and the output shaft 64 is rotatably supported with respect to the fixed case 62 by a bearing 66.

As shown in FIG. 6, the entry end portion of the output shaft 64 in the fixed case 62 is a hexagonal enlarged end portion 64a when viewed in the axial direction.
Between the outer peripheral flat surface forming each side of the hexagonal enlarged end portion 64a and the inner peripheral surface of the fixed case 62, a pair of biting rollers 67L and 67R is provided, and the roller axis line is the input / output shafts 63 and 64. Arranged so that it is parallel to the axis of

As shown in FIGS. 4 and 6, the springs 68 are interposed between the biting rollers 67L and 67R, and the biting rollers 67L and 67R are urged away from each other.
As a result, the biting rollers 67L and 67R are arranged in the circumferential direction between the corresponding outer peripheral flat surface of the hexagonal enlarged end portion 64a and the inner peripheral surface of the fixed case 62, as shown in FIG. 4 and FIG. Engage in the gradually decreasing gap.

As shown in FIG. 4 and FIG. 6 (a), at the entry end of the input shaft 63 in the fixed case 62, a pair of biting rollers 67L and 67R are sandwiched from both sides of the roller arrangement direction of the roller cage. For this purpose, roller holding claws 63L and 63R are provided at the minimum gaps between the respective corners of the hexagonal enlarged end portion 64a and the inner peripheral surface of the fixed case 62.
Accordingly, a gap is normally present between the roller holding claws 63L and 63R and the rollers 67L and 67R adjacent thereto, as indicated by α in FIG. 6 (a).

As shown in FIGS. 5 and 6 (a), the input end portion 63 of the input shaft 63 in the fixed case 62 is further provided with a plurality of drive pins 63a protruding in the axial direction toward the hexagonal enlarged end portion 64a.
A blind hole 64b in which each of these drive pins 63a is loosely fitted with a predetermined radial gap β (β> α) is formed in the end face of the hexagonal enlarged end portion 64a.

  As shown in FIG. 2, the torque diode 61 configured as described above has the case 62 fixed to the housing 57c of the reduction gear box 57, and the input shaft 63 is coupled to the output shaft 58a of the inter-roller radial pressing force control motor 58. Then, the output shaft 64 is coupled to the input shaft 59 of the reduction gear box 57 and is practically used in the driving force distribution device 1.

<For irreversible operation of torque diode>
The operation of the torque diode 61 will be described below with reference to FIGS. 6 (a), (b), and (c).
FIG. 6 (a) shows a state when the motor 58 of FIG. 2 is not operating and no torque is input from the motor 58 to the input shaft 63. FIG.
In this case, the roller holding claws 63L and 63R of the input shaft 63 are in neutral positions separated from the adjacent rollers 67L and 67R by a gap α, respectively, and the drive pin 53a of the input shaft 63 is connected to the output shaft 64 (hexagonal enlargement). At the center of the blind hole 64b provided at the end 64a).

Even if there is a reverse input from the output shaft 64 (hexagonal enlarged end portion 64a) in this state, the output shaft 64 (hexagonal enlarged end portion 64a) is prevented from rotating as follows.
When the reverse input from the output shaft 64 (hexagonal enlarged end portion 64a) is the torque in the hour hand direction in FIG. 6 (a), the corner portion on the torque direction delay side of the hexagonal enlarged end portion 64a The roller 67L is further engaged between the inner peripheral surface and the rotation of the output shaft 64 (hexagonal enlarged end portion 64a) due to reverse input.
When the reverse input from the output shaft 64 (hexagonal enlarged end 64a) is the counterclockwise direction torque in FIG. 6 (a), the corner of the hexagonal enlarged end 64a on the delay side in the torque direction is a fixed case. The roller 67R is further engaged between the inner peripheral surface 62 and the rotation of the output shaft 64 (hexagonal enlarged end portion 64a) due to reverse input.

  Therefore, the output shaft 64 (hexagonal enlarged end portion 64a) is not rotated by the reverse input in any of the above directions while no torque is input to the input shaft 63 due to the non-operation of the motor 58 of FIG. The current rotational position can be maintained, and the crankshafts 51L and 51R can be maintained at the current rotational position. Due to this irreversible transmission operation, the radial pressing force between the rollers 31 and 32 (transfer torque capacity between the rollers), that is, driving The power distribution ratio can be maintained as it is.

  If torque is input to the input shaft 63 due to the operation of the motor 58 shown in FIG. 2, the torque diode 61 transmits this torque to the hexagonal enlarged end portion 64a (output shaft 64) as follows. However, it can be directed to the driving force distribution control system.

The case where the torque from the motor 58 to the input shaft 63 is in the direction indicated by the arrows in FIGS. 6B and 6C will be described.
After the roller holding claw 63L on the rotation direction delay side of the input shaft 63 rotates by the clearance α, it comes into contact with the corresponding roller 67L as shown in FIG. 6 (b), and this roller 67L is opposed to the spring 68 against the roller 67R. By pushing in the approaching direction, as shown in FIG. 6C, the distance between the corresponding outer peripheral flat surface of the hexagonal enlarged end portion 64a and the inner peripheral surface of the fixed case 62 is displaced.

The roller 67R releases the rotation lock of the hexagonal enlarged end portion 64a (output shaft 64) with respect to the fixed case 62 by such displacement.
When the rotation lock is released, as shown in FIG. 6 (c), the drive pin 63a of the input shaft 63 is engaged with the inner peripheral surface of the blind hole 64b by the rotation of the gap β, and the input shaft 63 is connected to the drive pin 63a. Torque is transmitted to the hexagonal enlarged end 64a (output shaft 64) through engagement with the blind hole 64b, and the radial pressing force between the rollers 31 and 32 (transfer torque capacity between the rollers), that is, the driving force distribution ratio Can be arbitrarily controlled by adjusting the torque (torque control of the motor 58).

Even when the torque from the motor 58 to the input shaft 63 is in the reverse direction as shown by the arrows in FIGS. 6B and 6C, the roller holding claw 63R on the rotation direction delay side of the input shaft 63 has the clearance α After rotating only, the roller 67R is pressed against the corresponding roller 67R to release the rotation lock,
At this time, the driving pin 63a of the input shaft 63 transmits torque to the hexagonal enlarged end portion 64a (output shaft 64) through the engagement with the blind hole 64b, so that the radial pressing force between the rollers 31 and 32 ( The inter-roller transmission torque capacity), that is, the driving force distribution ratio can be arbitrarily controlled by adjusting the torque.

<Driving force distribution control>
FIG. 7 shows a driving force distribution control system using the inter-roller radial pressing force control motor 58. This system has a transfer controller 71 as a main component.
The transfer controller 71 includes a required torque capacity calculating unit 72 for calculating a required torque capacity Treq between the first roller 31 and the second roller 32,
In order to achieve this required torque capacity Treq, it is constituted by a resolution switching unit 73 for switching the resolution used when calculating the necessary current i to be supplied to the inter-roller radial pressing force control motor 58.

The transfer controller 71 has
A signal from the engine torque calculation unit 74 for calculating the output torque Te of the engine 2;
A signal from the accelerator opening sensor 75 for detecting the accelerator opening (accelerator pedal depression amount) APO of the engine 2;
A signal from the gear ratio sensor 76 for detecting the selected gear ratio γ of the transmission 3,
A vehicle behavior control VDC (Vehicle Dynamic Control) device and an anti-skid device ABS (Anti-Lock Brake System) 77 VDC flag indicating that the VDC is operating and an ABS flag indicating that the ABS is operating;
Yaw rate φ for VDC and ABS, lateral acceleration Gy, longitudinal acceleration Gx, yaw rate sensor 78 for detecting wheel speed Vw, lateral G sensor 79, longitudinal G sensor 81, signals from wheel speed sensor 82, and
A signal from the steering angle sensor 83 that detects the steering angle θ is input.

The transfer controller 71 including the required torque capacity calculation unit 72 and the resolution switching unit 73 executes the control program of FIG. 8 based on the above input information, and calculates the required current i to the inter-roller radial pressing force control motor 58. Calculate.
First, in step S11, the steering angle θ, wheel speed Vw, longitudinal acceleration Gx, lateral acceleration Gy, yaw rate φ, engine torque Te, accelerator opening APO, transmission gear ratio γ, ABS flag, and VDC flag are read.

In the next step S12, a required torque capacity Treq between the first roller 31 and the second roller 32 is calculated.
In this calculation, the required torque capacity calculation unit 72 in FIG. 7, for example, out of the wheel speed Vw, the main driving wheel speed related to the left and right rear wheels 6L, 6R as the main driving wheel and the left and right front wheels 9L as the sub driving wheel Compared with the driven wheel speed related to 9R, the driving slip condition of the main driving wheels 6L, 6R is checked one by one, and the target driving force required to keep this main driving wheel slip within the allowable range The distribution ratio is obtained from the engine torque Te, the accelerator opening APO, and the transmission gear ratio γ, and the transmission torque capacity between the first roller 31 and the second roller 32 necessary to achieve this target driving force distribution ratio is calculated. This is defined as the required torque capacity Treq between the rollers (corresponding to the required value of the pressing force between the rollers in the radial direction in the present invention).

Therefore, in this embodiment, the required torque capacity Treq is not used as it is for the drive control of the inter-roller radial direction pressing force control motor 58, and the command torque capacity Ttgt (the inter-roller radial direction in the present invention) is controlled by the resolution switching unit 73 of FIG. This command torque capacity Ttgt contributes to the drive control of the inter-roller radial direction pressing force control motor 58.
First, the resolution switching unit 73 determines whether or not any of the wheels 6L, 6R, 9L, 9R is steered from the steering angle θ, the yaw rate φ, the lateral acceleration Gy, the longitudinal acceleration Gx, etc. in step S13 of FIG. And whether the ABS flag or the VDC flag is ON or whether the VDC is operating is checked.

  In step S13, the resolution switching unit 73 in FIG. 7 determines that none of the wheels 6L, 6R, 9L, and 9R is steered (straightly traveling), and both the ABS flag and the VDC flag are OFF (ABS is not activated, VDC In step S14, a low-resolution map for non-request for high-precision driving force distribution control exemplified by a solid line in FIG. 9A is selected in step S14, and this low resolution is selected in the next step S16. The command torque capacity Ttgt is searched from the necessary torque capacity Treq based on a simple map.

Next, in step S17, a motor required current value i is calculated to realize the inter-roller radial pressing force command value necessary for the transmission torque capacity between the first roller 31 and the second roller 32 to become the command torque capacity Ttgt. And
In the next step S18, the motor required current value i is commanded to the inter-roller radial pressing force control motor 58.

However, the resolution switching unit 73 in FIG. 7 determines in step S13 that one of the wheels 6L, 6R, 9L, 9R is being steered, or the ABS flag or VDC flag is ON (ABS is operating or VDC In step S15, a high-resolution map for requesting high-precision driving force distribution control exemplified by the solid line in FIG. 9B is selected in step S15.
Based on this map, in subsequent steps S16 to S18, the command torque capacity Ttgt is obtained, and the diameter between the rollers necessary for the transmission torque capacity between the first roller 31 and the second roller 32 to become the command torque capacity Ttgt. The motor required current value i for realizing the direction pressing force command value is calculated, and this motor required current value i is commanded to the inter-roller radial direction pressing force control motor 58.

Here, the high-resolution map for requesting the high-precision driving force distribution control exemplified by the solid line in FIG. 9B is such that the required torque capacity Treq obtained in step S12 is directly used as the command torque capacity Ttgt. Needless to say, this is preferable in the sense of satisfying the high-precision driving force distribution control requirement.
In addition, in this case, the required torque capacity Treq obtained in step S12 is used as it is as the command torque capacity Ttgt in step S16. Therefore, the high-accuracy driving force distribution control request illustrated by the solid line in FIG. A high-resolution map for time is not necessary, and the memory capacity can be reduced accordingly.

  As is apparent from the above description, the resolution switching unit 73 in FIG. 7 constitutes an operation state determination unit and a command value resolution switching unit in the present invention.

Note that the low-resolution map illustrated by the solid line in FIG. 9 (a) and the high-resolution map illustrated by the solid line in FIG. 9 (b) are located in the region above the broken line characteristic of Ttgt = Treq, that is, The command torque capacity Ttgt is preferably set in advance in association with the required torque capacity Treq so that the command torque capacity Ttgt is always equal to or greater than the required torque capacity Treq.
In this case, the actual transmission torque capacity between the rollers 31 and 32 provided by the inter-roller radial pressing force control motor 58 driven and controlled by the required current value i corresponding to the command torque capacity Ttgt is less than the required torque capacity Treq. It is possible to avoid the inconvenience that a slip occurs between 31 and 32 and the expected driving force distribution control cannot be expected.

By the way, in this embodiment, a motor is required to realize the inter-roller radial pressing force command value necessary for the transmission torque capacity between the first roller 31 and the second roller 32 to become the command torque capacity Ttgt in step S17. When calculating the current value i, this calculation is performed as follows.
In FIGS. 9 (a) and 9 (b), while the command torque capacity Ttgt maintains a constant value that is invariable with respect to the required torque capacity Treq, the motor required current value i = 0 as described above by the installation of the torque diode 61 described above. Even if the inter-roller radial pressing force control motor 58 is inactivated, the inter-roller radial pressing force command value continues to be realized and the transmission torque capacity between the first roller 31 and the second roller 32 is determined as the command torque. The capacity Ttgt can be held.
Therefore, after the inter-roller transmission torque capacity reaches the command torque capacity Ttgt, as long as the command torque capacity Ttgt maintains a constant value that does not change, the motor required current value i = 0 causes the inter-roller radial pressing force control motor. 58 will be deactivated to reduce power consumption.

From the viewpoint of such power consumption, the low-resolution map illustrated by the solid line in FIG. 9 (a) is more advantageous than the high-resolution map illustrated by the solid line in FIG. 9 (b).
The reason for this is that in the case of a low-resolution map, the command torque capacity Ttgt remains constant for a long time with respect to the required torque capacity Treq, and the radial force between the rollers is controlled by the required motor current value i = 0. This is because 58 can be kept in a non-operating state for a long time.

  However, as described above, the command torque capacity Ttgt is associated with the required torque capacity Treq so that the command torque capacity Ttgt is always equal to or greater than the required torque capacity Treq, and is illustrated by a solid line in FIG. 9 (a). In the case of a low resolution map, the transmission torque capacity between rollers is more likely to be larger than the required torque capacity Treq than the high resolution map illustrated by the solid line in FIG. 9 (b), which is close to a so-called rigid four-wheel drive state. .

Therefore, when the command torque capacity Ttgt is obtained using a low-resolution map illustrated by a solid line in FIG. 9A during steering, there is a problem that the turning radius becomes large due to an understeer tendency due to a tight corner brake phenomenon.
In addition, when the command torque capacity Ttgt is obtained using the low-resolution map illustrated by the solid line in Fig. 9 (a) during ABS operation or VDC operation, the distribution of driving force required for ABS operation or VDC operation is obtained. It cannot be executed, causing a problem that a predetermined wheel braking lock preventing function and a predetermined vehicle behavior control function cannot be performed.

  Therefore, in the driving state where high-precision driving force distribution control is required, such as during steering, ABS operation, or VDC operation, the high-resolution map illustrated by the solid line in Fig. 9 (b) is used. Thus, by obtaining the command torque capacity Ttgt, it is necessary that the inter-roller transmission torque capacity does not become much larger than the required torque capacity Treq so that it does not become a so-called rigid four-wheel drive state.

  On the other hand, in the driving state where high accuracy driving force distribution control is not required, such as when the vehicle is traveling straight and both ABS and VDC are not operating, the state is close to a so-called rigid four-wheel drive state. However, since there is no need to worry about the above problems, the command torque capacity Ttgt is obtained based on the low-resolution map illustrated by the solid line in FIG. Is good.

When the above is straight and ABS and VDC are not operating as in this embodiment, the command torque is calculated from the required torque capacity Treq based on the low-resolution map illustrated in FIG. I want to find the capacity Ttgt,
When steering or ABS or VDC is operating, command torque capacity Ttgt is calculated from required torque capacity Treq based on the high-resolution map illustrated in Fig. 9 (b). That is why.

<Operational effects of the first embodiment>
The operation and effect of the driving force distribution device of the first embodiment shown in FIGS. 1 to 9 will be described below.
The output torque from the transmission 3 in FIG. 1 is input to the shaft 12 from the left end of FIG. 2, and on the other hand, the left and right rear wheels 6L, 6R (mainly) from the input shaft 12 pass through the rear propeller shaft 4 and the rear final drive unit 5 as they are. Drive wheel).

On the other hand, the driving force distribution device 1 directs a part of the torque to the left and right rear wheels 6L, 6R from the first roller 31 to the output shaft 13 through the second roller 32, and the torque reaching the output shaft 13 is 2, the signal is transmitted from the left end of the output shaft 13 to the left and right front wheels (slave drive wheels) 7L and 7R via the front propeller shaft 7 (see FIG. 1) and the front final drive unit 8 (see FIG. 1).
Thus, the vehicle is capable of four-wheel drive running by driving all of the left and right rear wheels 6L and 6R (main drive wheels) and the left and right front wheels (secondary drive wheels) 7L and 7R.

The driving force distribution control between the left and right rear wheels 6L, 6R and the left and right front wheels 7L, 7R during the four-wheel drive traveling is executed by the inter-roller radial pressing force control motor 58.
The rotation of the inter-roller radial pressing force control motor 58 reaches the crankshafts 51L and 51R via the torque diode 61, the reduction gear box 57, the pinions 55L and 55R, and the ring gears 51Lc and 51Rc.

Therefore, the rotational position of the crankshafts 51L and 51R can be controlled by the roller radial pressing force control motor 58,
The rotation axis O ₂ of the output shaft 13 and the second roller 32 turns along a locus circle indicated by a broken line in FIG. 3, and the change of the inter-axis distance between the rollers 31 and 32 causes the second roller 32 to move relative to the first roller 31. The radial pressing force, that is, the transmission torque capacity between the rollers 31 and 32 (front and rear wheel driving force distribution) can be controlled according to the calculation result of FIG.

By the way, in the present embodiment, the rotation of the inter-roller radial pressing force control motor 58 is transmitted to the reduction gear box 57 via the torque diode 61 in the above control.
Due to the irreversible transmission operation of the torque diode 61, while the command torque capacity Ttgt (the radial pressing force command value between the rollers) remains unchanged, even if the inter-roller radial pressing force control motor 58 is deactivated, the roller 31 and 32 The transmission torque capacity (the radial pressing force between the rollers) can be held at the command value Ttgt.
Therefore, in this embodiment, even during the driving force distribution control, a time during which the inter-roller radial pressing force control motor 58 can be deactivated, that is, a time during which the energy consumed for the driving force distribution control is set to 0 is generated. It is possible to suppress energy loss during driving force distribution control.

Further, in this embodiment, as the command torque capacity Ttgt, when the vehicle is running straight, the ABS and the VDC are not operating, and the driving state in which the highly accurate driving force distribution control is not necessary, Compared to the case of operation or operation state that requires high-accuracy driving force distribution control, such as during VDC operation, the time during which the command torque capacity Ttgt is an invariable constant value is long, FIG. 9 (a) In order to perform operation control of the inter-roller radial pressing force control motor 58 using the low-resolution command torque capacity Ttgt illustrated by the solid line in FIG.
In an operating state where high-accuracy driving force distribution control is not required, the command torque capacity Ttgt is a constant value that remains unchanged, i.e., the in-roller radial direction pressing force control motor 58 is not operated during driving force distribution control. The time to keep the energy consumption to 0 becomes longer,
It is possible to solve the above-mentioned problem of the prior art that the energy loss during the driving force distribution control becomes large.

In addition, of course, if the low-resolution command torque capacity Ttgt is used, the driving force distribution control also becomes low accuracy.
If the driving force distribution control does not require high-accuracy driving force distribution control, the low-resolution command torque capacity Ttgt is used for the driving force distribution control because the driving force distribution control does not cause any problems even if the accuracy is low. There is no problem.

  On the other hand, when the driving state requires high-accuracy driving force distribution control, a solid line in FIG. 9 (b) replaces the low-resolution command torque capacity Ttgt illustrated in FIG. 9 (a) with a solid line. Since the exemplified high-resolution command torque capacity Ttgt is used, highly accurate driving force distribution control can be performed as planned without sacrificing this.

Therefore, according to the present embodiment, within a range where the driving force distribution control is not adversely affected, the time during which the energy consumed for the control can be set to 0 can be made as long as possible.
It is possible to reliably solve the above-described problem of the prior art that the energy loss during the control is suppressed without affecting the driving force distribution control and the energy loss is increased.

Further, in this embodiment, the low-resolution command torque capacity Ttgt (roller radial direction pressing force command value) and the high-resolution command torque capacity Ttgt (roller radial direction pressing force command value) are respectively shown in FIGS. As illustrated by a solid line in (b), a predetermined torque map Treq between the first roller 31 and the second roller 32 (necessary value for pressing force between the rollers in the radial direction) is determined in advance and mapped,
When it is an operation state that does not require high-accuracy driving force distribution control, based on the map of FIG. 9 (a), search and obtain a low-resolution command torque capacity Ttgt,
Also, when the driving state requires high-accuracy driving force distribution control, the high-resolution command torque capacity Ttgt is retrieved from the required torque capacity Ttgt between the rollers based on the map shown in Fig. 9 (b). From
Although the memory capacity for maps is large, the calculation load of the command torque capacity Ttgt is small, and a high-performance and expensive calculation system is not required, which is advantageous in terms of cost.

  In addition, instead of the high-resolution command torque capacity map for requesting high-precision driving force distribution control exemplified by the solid line in FIG. 9 (b), the required torque capacity Treq between rollers is set as the command torque capacity Ttgt as it is. In addition to satisfying the demand for accurate driving force distribution control, the high-resolution map for requesting high-precision driving force distribution control illustrated by the solid line in Fig. 9 (b) is not required, and the memory capacity is reduced accordingly. There are advantages that can be done.

In this embodiment, the low-resolution command torque capacity Ttgt and the high-resolution command torque capacity Ttgt are set to values that are equal to or greater than the required torque capacity Ttgt between rollers, as illustrated by solid lines in FIGS. 9 (a) and 9 (b), respectively. Because it was determined in association with this to be retained,
The actual transmission torque capacity between the rollers 31 and 32 provided by the inter-roller radial pressing force control motor 58 controlled by the required current value i (steps S17 and S18 in FIG. 8) corresponding to the command torque capacity Ttgt is the required torque. It is possible to avoid the inconvenience that the drive force distribution control cannot be expected as expected due to slippage between the rollers 31 and 32 without being less than the capacity Treq.

<Second embodiment>
In this embodiment, a low-resolution command torque capacity Ttgt as shown in FIG. 10 is used in place of the low-resolution command torque capacity Ttgt illustrated by a solid line in FIG. 9A.
In the present embodiment, the solid line characteristic shown in FIG. 10 is the same characteristic as shown by the solid line in FIG. 9 (a), except that this is a characteristic when the low-resolution command torque capacity Ttgt increases step by step. To do.
When the low-resolution command torque capacity Ttgt decreases one step at a time, as shown by the alternate long and short dash line in FIG. Set hysteresis between.

<Effect of the second embodiment>
In the case of the low-resolution command torque capacity Ttgt illustrated by the solid line in FIG. 9 (a), the required torque capacity Treq when the command torque capacity Ttgt is increased and decreased is the same value. When the motor changes in vibration, the command torque capacity Ttgt is frequently moved up and down in response to this, and the control becomes unstable.
Such frequent changes in the command torque capacity Ttgt cause the operation of the inter-roller radial pressing force control motor 58 to increase the power consumption, which goes against the power consumption reduction that is the gist of the present invention. .

However, when hysteresis is set as in this embodiment, the required torque capacity Treq to increase and decrease the command torque capacity Ttgt differs by the amount of hysteresis, so the required torque capacity Treq changes oscillating within this hysteresis range. Even so, the command torque capacity Ttgt does not move up and down to cause a hunting phenomenon.
Therefore, even if the required torque capacity Treq changes oscillating within the above hysteresis range, the inter-roller radial pressing force control motor 58 is not operated, and the motor 58 can be maintained in a non-operating state. In addition, it is possible to reliably achieve the object of the present invention so that power consumption can be suppressed in an operating state where high-precision driving force distribution control is not required.

<Third embodiment>
In this embodiment, the command torque capacity Ttgt with high resolution is set to the same value as the required torque capacity Treq between the first roller 31 and the second roller 32.
However, the low-resolution command torque capacity Ttgt is the required torque capacity Treq between the first roller 31 and the second roller 32 as shown in the first and second embodiments, that is, as shown in FIGS. 9 (a) and 10. Instead of mapping in advance,
As shown in FIG. 11, it is determined and determined every moment based on the required torque capacity Treq between the first roller 31 and the second roller 32.

In this calculation, as shown in FIG. 11, the low-resolution command torque capacity Ttgt is set to an initial value that is increased from 0 to the first stage at the rising instant t1 of the required torque capacity Treq,
After that, increase side reference value (Ttgt + A) larger by increase side dead band A and decrease side reference value (Ttgt−B) by decrease side dead band B (= A) than current low resolution command torque capacity Ttgt. Based on this, the low-resolution command torque capacity Ttgt is increased by one step at the instant t2 when the required torque capacity Treq is greater than the increase side reference value (Ttgt + A), and the required torque capacity Treq is less than the decrease side reference value (Ttgt-B). (Not shown in FIG. 11), the low-resolution command torque capacity Ttgt is decreased by one step.

<Effect of the third embodiment>
Also in the present embodiment, the low-resolution command torque capacity Ttgt used in an operation state where high-precision driving force distribution control is not required, as shown in FIG. 11, takes a long time as an invariable constant value. .
Therefore, in this embodiment, as in the first and second embodiments, it is possible to keep the inter-roller radial pressing force control motor 58 in a non-operating state with zero energy consumption while preventing adverse effects on the driving force distribution control. It is possible to reliably solve the above-described problem of the prior art that the time that can be increased, energy loss during driving force distribution control is suppressed, and this energy loss increases.

  In addition, according to the present embodiment, the memory capacity for the map, which is indispensable in the first and second embodiments, is unnecessary, and in addition, when the required torque capacity Treq is equal to or greater than the increase side reference value (Ttgt + A), the resolution is low. When the required torque capacity Ttgt is increased by one step and the required torque capacity Treq is less than the decrease side reference value (Ttgt-B), the low-resolution command torque capacity Ttgt is decreased by one step. It is possible to prevent the command torque capacity Ttgt having a low resolution from fluctuating (hunting) in response to the change.

<Fourth embodiment>
Also in the present embodiment, the high-resolution command torque capacity Ttgt is set to the same value as the required torque capacity Treq between the first roller 31 and the second roller 32 as in the third embodiment.
Also, the low-resolution command torque capacity Ttgt is determined by calculation from time to time based on the required torque capacity Treq between the first roller 31 and the second roller 32 as in the third embodiment. As shown, it is different from the third embodiment.

That is, in the fourth embodiment, as shown in FIG. 12, the low-resolution command torque capacity Ttgt is set to an initial value that is increased by 0 from the first stage ΔTa from 0 at the rising instant t1 of the required torque capacity Treq,
Thereafter, based on the current low-resolution command torque capacity Ttgt and the decrease side reference value (Ttgt-C) smaller by the decrease-side dead band C, the required torque capacity Treq is the current low-resolution command torque capacity. The command torque capacity Ttgt with low resolution is increased by one step ΔTb at the instant t2 when it exceeds Ttgt, and the command torque capacity Ttgt with low resolution at the instant t3 when the required torque capacity Treq is less than the decrease side reference value (Ttgt-C). Decrease by one step ΔTb.

<Effect of the fourth embodiment>
Also in this embodiment, as shown in FIG. 12, the low-resolution command torque capacity Ttgt used in the operation state where high-accuracy driving force distribution control is not required has a long time that is an invariable constant value. .
Therefore, in the present embodiment, as in each of the above embodiments, the energy loss during the driving force distribution control is suppressed and the energy loss is increased while the driving force distribution control is not adversely affected. The problems of the prior art can be solved reliably.

In addition, according to the present embodiment, when the required torque capacity Treq is equal to or higher than the current low resolution command torque capacity Ttgt, the low resolution command torque capacity Ttgt is increased by one step ΔTb, and the required torque capacity Treq is reduced by the reference value. (Ttgt−C) Since the low-resolution command torque capacity Ttgt is decreased by one step ΔTb when the value becomes less than (Ttgt−C), the low-resolution command torque capacity Ttgt fluctuates in response to the vibrational change in the required torque capacity Treq ( Hunting) can be prevented.
In addition, according to the present embodiment, the command torque capacity Ttgt never becomes less than the required torque capacity Treq, and slip occurs between the rollers 31 and 32 due to this Ttgt <Treq, and drive force distribution control as planned. Can be avoided.

<Fifth embodiment>
Also in this embodiment, the high-resolution command torque capacity Ttgt is set to the same value as the required torque capacity Treq between the first roller 31 and the second roller 32, as in the third and fourth embodiments.
In addition, the low-resolution command torque capacity Ttgt is determined by calculating from time to time based on the required torque capacity Treq between the first roller 31 and the second roller 32, as in the third and fourth embodiments. The point is as shown in FIG. 13, which is different from the third embodiment and the fourth embodiment.

That is, in the fifth embodiment, as shown in FIG. 13, the low-resolution command torque capacity Ttgt is set to an initial value that is increased from 0 to the first stage ΔTa from 0 at the rising instant t1 of the required torque capacity Treq,
Thereafter, an increase side reference value (Ttgt−D) that is smaller than the current low-resolution command torque capacity Ttgt by an increase side dead zone D, and a decrease side dead zone E that is further lower than the increase side reference value (Ttgt−D). Based on a decrease side reference value (Ttgt-D-E) that is only small, the command torque capacity Ttgt with low resolution is reduced by one step ΔTb at the instant t2 when the required torque capacity Treq is greater than the increase side reference value (Ttgt-D). The command torque capacity Ttgt having a low resolution is decreased by one step ΔTb at the instant t3 when the required torque capacity Treq becomes equal to or less than the decrease side reference value (Ttgt−D−E).

<Effect of the fifth embodiment>
Also in the present embodiment, the low-resolution command torque capacity Ttgt used in an operation state where high-precision driving force distribution control is not required, as shown in FIG. 13, takes a long time as an invariable constant value. .
Therefore, in the present embodiment, as in each of the above embodiments, the energy loss during the driving force distribution control is suppressed and the energy loss is increased while the driving force distribution control is not adversely affected. The problems of the prior art can be solved reliably.

Further, according to the present embodiment, when the required torque capacity Treq is equal to or greater than the increase side reference value (Ttgt−D), the low-resolution command torque capacity Ttgt is increased by one step ΔTb, and the required torque capacity Treq is decreased on the decrease side reference value. (Ttgt-D-E) Since the low-resolution command torque capacity Ttgt is decreased by one step ΔTb when it becomes less than or equal to (Ttgt-D-E), the low-resolution command torque capacity Ttgt responds to this by the vibrational change of the required torque capacity Treq. Fluctuation (hunting) can be prevented.
In addition, according to the present embodiment, the command torque capacity Ttgt never becomes less than the required torque capacity Treq, and slip occurs between the rollers 31 and 32 due to this Ttgt <Treq, and drive force distribution control as planned. Can be avoided.

As in the fourth embodiment shown in FIG. 12, the low-resolution command torque capacity Ttgt is increased by one step ΔTb at the instant t2 when the required torque capacity Treq is equal to or greater than the current low-resolution command torque capacity Ttgt. In this case, there is a concern that the command torque capacity Ttgt temporarily becomes less than the required torque capacity Treq due to a response delay and slip occurs between the rollers 31 and 32.
However, in the present embodiment, an increase side reference value (Ttgt−D) that is smaller by the increase side dead band D than the current low resolution command torque capacity Ttgt is used, and the required torque capacity Treq is the increase side reference value (Ttgt−D). ) Because the low-resolution command torque capacity Ttgt is increased by one step ΔTb at the instant t2
The command torque capacity Ttgt does not become less than the required torque capacity Treq due to a response delay, and the above-mentioned concern that a slip occurs between the rollers 31 and 32 can be eliminated.

<Sixth embodiment>
Also in this embodiment, the high-resolution command torque capacity Ttgt is set to the same value as the required torque capacity Treq between the first roller 31 and the second roller 32, as in the third to fifth embodiments.
Also, the low-resolution command torque capacity Ttgt is obtained and determined from time to time based on the required torque capacity Treq between the first roller 31 and the second roller 32, as in the third to fifth embodiments. As shown in FIG. 14, it is different from the third to fifth embodiments.

That is, in the sixth embodiment, as shown in FIG. 14, the low-resolution command torque capacity Ttgt is increased from 0 to the maximum value at the rising instant t1 of the required torque capacity Treq,
Thereafter, at the instant t2 when the required torque capacity Treq disappears, the low-resolution command torque capacity Ttgt is set to 0 from the maximum value.

<Effects of the sixth embodiment>
Also in the present embodiment, the low-resolution command torque capacity Ttgt used in an operation state where high-accuracy driving force distribution control is not required, as shown in FIG. In this embodiment, this constant value time is longer than in any embodiment.
Therefore, according to the present embodiment, as in each of the embodiments described above, the energy loss at the time of the driving force distribution control is suppressed and the energy loss is increased while the driving force distribution control is not adversely affected. The problems of the prior art described above can be solved more reliably than any of the embodiments, and the hunting prevention effect of the low-resolution command torque capacity Ttgt when the required torque capacity Treq is oscillating is significantly more pronounced than any of the embodiments. Can play.

  In addition, according to the present embodiment, the command torque capacity Ttgt never becomes less than the required torque capacity Treq, and slip occurs between the rollers 31 and 32 due to this Ttgt <Treq, and drive force distribution control as planned. Can be avoided.

<Other examples>
In each of the above embodiments, the case where the torque diode 61 as shown in FIGS. 2, 4, 5 and 6 is used as the irreversible transmission mechanism to be inserted into the driving force distribution control system has been described. However, the torque diode 61 is used as the irreversible transmission mechanism. Of course, other irreversible transmission mechanisms such as a worm gear box composed of a worm and a worm wheel may be used.
However, since the transmission efficiency of the worm gear box or the like is poorer than that of the torque diode 61, the use of the torque diode 61 is advantageous in terms of both lightness of driving force distribution control and power consumption.

1 Driving force distribution device
2 Engine
3 Transmission
4 Rear propeller shaft
5 Rear final drive unit
6L, 6R Left and right rear wheels (main drive wheels)
7 Front propeller shaft
8 Front final drive unit
9L, 9R Left and right front wheels (sub driven wheels)
11 Housing
12 Input shaft
13 Output shaft
16,17 Bearing support
31 1st roller
32 2nd roller
51L, 51R Crankshaft
51La, 51Ra Center hole
51Lb, 51Rb Eccentric outer periphery
51Lc, 51Rc Ring gear
55L, 55R Crankshaft drive pinion
56 Pinion shaft
57 Reduction gear box
58 Roller radial pressing force control motor (Roller radial pressing force source)
61 Torque diode (irreversible transmission mechanism)
62 Fixed case
63 Input shaft
63a Drive pin
63L, 63R Roller holding claw
64 output shaft
64a Hexagonal enlarged end
64b blind hole
65,66 Bearing
67L, 67R Bite roller
68 Spring
71 Transfer controller
72 Required torque capacity calculator
73 Resolution switching unit (operating state determination means and command value resolution switching means)
74 Engine torque calculator
75 Accelerator position sensor
76 Gear ratio sensor
77 Vehicle behavior control device and anti-skid device ABS
78 Yaw rate sensor
79 G sensor
81 Front / rear G sensor
82 Wheel speed sensor
83 Steering angle sensor

Claims (11)

A first roller mechanically coupled to the main drive wheel;
A second roller that is mechanically coupled to the driven wheel and distributes the driving force to the driven wheel by frictional contact with the first roller;
In the driving force distribution device configured to control the driving force distribution between the main driving wheel and the sub driving wheel by adjusting the radial pressing force between the first roller and the second roller,
In order to increase or decrease the radial pressing force between the first roller and the second roller so as to become a command value, the operating force from the roller radial pressing force source that responds to the roller radial pressing force command value is irreversibly reduced. An irreversible transmission mechanism is provided so that the roller-to-roller radial pressing force command value remains constant while the roller-to-roller radial pressing force generation source is inactive. No so that you can hold on to
A state in which at least one of the main drive wheel and the sub drive wheel is steered is determined as an operation state in which high-precision driving force distribution control between the main drive wheel and the sub drive wheel is required, and these main drive with the state of wheel and auxiliary driving wheels are not steered all, the main driving wheels and auxiliary driving precision driving force distribution control is not required operating state and determining operating condition determining means between driving wheel,
When it is determined by the driving state determining means that the driving state is not required for high-precision driving force distribution control, the driving state is not changed compared to the driving state where high-precision driving force distribution control is required. A driving force distribution comprising: a low-resolution radial pressing force command value between rollers for a long time, and command value resolution switching means for contributing to operation control of the radial pressing force generation source between the rollers apparatus. A first roller mechanically coupled to the main drive wheel;
A second roller that is mechanically coupled to the driven wheel and distributes the driving force to the driven wheel by frictional contact with the first roller;
In the driving force distribution device configured to control the driving force distribution between the main driving wheel and the sub driving wheel by adjusting the radial pressing force between the first roller and the second roller,
In order to increase or decrease the radial pressing force between the first roller and the second roller so as to become a command value, the operating force from the roller radial pressing force source that responds to the roller radial pressing force command value is irreversibly reduced. An irreversible transmission mechanism is provided so that the roller-to-roller radial pressing force command value remains constant while the roller-to-roller radial pressing force generation source is inactive. No so that you can hold on to
A state in which at least one of the main driving wheel and the sub driving wheel is controlled to prevent braking lock is determined as an operating state in which high-precision driving force distribution control between the main driving wheel and the sub driving wheel is required. Driving state determination means for determining that the main driving wheel and the sub driving wheel are not subjected to the brake lock prevention control and the driving state where high-precision driving force distribution control between the main driving wheel and the sub driving wheel is not required;
When it is determined by the driving state determining means that the driving state is not required for high-precision driving force distribution control, the driving state is not changed compared to the driving state where high-precision driving force distribution control is required. A driving force distribution comprising: a low-resolution radial pressing force command value between rollers for a long time, and command value resolution switching means for contributing to operation control of the radial pressing force generation source between the rollers apparatus. A first roller mechanically coupled to the main drive wheel;
A second roller that is mechanically coupled to the driven wheel and distributes the driving force to the driven wheel by frictional contact with the first roller;
In the driving force distribution device configured to control the driving force distribution between the main driving wheel and the sub driving wheel by adjusting the radial pressing force between the first roller and the second roller,
In order to increase or decrease the radial pressing force between the first roller and the second roller so as to become a command value, the operating force from the roller radial pressing force source that responds to the roller radial pressing force command value is irreversibly reduced. An irreversible transmission mechanism is provided so that the roller-to-roller radial pressing force command value remains constant while the roller-to-roller radial pressing force generation source is inactive. No so that you can hold on to
Driving in which at least one of the main driving wheel and the sub driving wheel is subjected to braking / driving force control for vehicle behavior control, and high-precision driving force distribution control between the main driving wheel and the sub driving wheel is required. It is determined that the main drive wheel and the sub drive wheel are in a state where neither the main drive wheel nor the sub drive wheel is subjected to braking / driving force control for vehicle behavior control, and high-precision driving force distribution control between the main drive wheel and the sub drive wheel is required. Driving state determination means for determining that the driving state is not,
When it is determined by the driving state determining means that the driving state is not required for high-precision driving force distribution control, the driving state is not changed compared to the driving state where high-precision driving force distribution control is required. A driving force distribution comprising: a low-resolution radial pressing force command value between rollers for a long time, and command value resolution switching means for contributing to operation control of the radial pressing force generation source between the rollers apparatus. In the driving force distribution device according to any one of claims 1 to 3 ,
The command value resolution switching means predetermines the low-resolution radial pressing force command value between rollers in association with the required radial pressing force value between the first roller and the second roller,
When it is determined by the operation state determination means that the operation state does not require high-precision driving force distribution control, the low-resolution inter-roller radial pressing force command value is calculated from the required radial pressing force between the rollers. A driving force distribution device characterized by being searched for. In the driving force distribution device according to claim 4 ,
The low-resolution radial pressing force command value between rollers is associated with the required radial pressing force value between the rollers so as to be maintained at a value that is equal to or greater than the required radial roller pressing force value. A driving force distribution device characterized by the above. In the driving force distribution device according to claim 4 or 5 ,
The low-resolution inter-roller radial pressing force command value has a hysteresis set so as to decrease at a lower required radial radial pressing force value than the required radial radial pressing force value at the time of ascent. Driving force distribution device. In the driving force distribution device according to any one of claims 1 to 3 ,
The command value resolution switching means obtains and determines the low-resolution inter-roller radial pressing force command value by calculation based on the required radial pressing force value between the first roller and the second roller. ,
The low-resolution radial pressing force command value between the rollers is an initial value that is increased from 0 to the first stage at the rise of the required radial pressing force value between the rollers,
After that, based on the increase side deadline value that is larger by the increase side dead band and the decrease side reference value that is smaller by the decrease side dead band than the low resolution radial pressure force command value of the roller, the required radial force force between the rollers Increase the low-diameter radial pressing force command value between rollers by 1 step when the value exceeds the reference value on the increasing side, and reduce the distance between the low-resolution rollers when the required radial pressing force value between the rollers falls below the decreasing reference value. A driving force distribution device that reduces the radial pressing force command value by one step. In the driving force distribution device according to any one of claims 1 to 3 ,
The command value resolution switching means obtains and determines the low-resolution inter-roller radial pressing force command value by calculation based on the required radial pressing force value between the first roller and the second roller. ,
The low-resolution radial pressing force command value between the rollers is an initial value that is increased from 0 to the first stage at the rise of the required radial pressing force value between the rollers,
Thereafter, the radial direction between the rollers is based on the low-resolution radial pressing force command value between the rollers and the reduced reference value that is smaller than the low-resolution radial pressing force command value by the reduced dead zone. When the required pressing force value is greater than or equal to the low resolution radial pressing force command value between rollers, the low resolution radial pressing force command value between rollers is increased by one step, and the required radial pressing force value between the rollers decreases. A driving force distribution device that reduces a low-resolution inter-roller radial pressing force command value by one step when the value is below a reference value. In the driving force distribution device according to any one of claims 1 to 3 ,
The command value resolution switching means obtains and determines the low-resolution inter-roller radial pressing force command value by calculation based on the required radial pressing force value between the first roller and the second roller. ,
The low-resolution radial pressing force command value between the rollers is an initial value that is increased from 0 to the first stage at the rise of the required radial pressing force value between the rollers,
Thereafter, based on the increasing reference value smaller by the increasing dead zone than the low-resolution radial pressing force command value between the rollers, and the decreasing reference value smaller by the decreasing dead band than the increasing reference value. When the required radial pressing force between the rollers is greater than the reference value on the increase side, the low-resolution radial pressing force command value between the rollers is increased by one step, and the required radial pressing force between the rollers is reduced on the decreasing reference A driving force distribution device that reduces a low-resolution radial pressing force command value between rollers by one step when the value is less than the value. In the driving force distribution device according to any one of claims 1 to 3 ,
The command value resolution switching means obtains and determines the low-resolution inter-roller radial pressing force command value by calculation based on the required radial pressing force value between the first roller and the second roller. ,
The low-resolution inter-roller radial pressing force command value is increased from 0 to the maximum value at the rise of the inter-roller radial pressing force required value, and from the maximum value to 0 at the disappearance of the inter-roller radial pressing force value. The driving force distribution device is characterized in that the driving force distribution device decreases. In the driving force distribution device according to any one of claims 1 to 10 ,
The command value resolution switching means should contribute to the operation control of the inter-roller radial pressing force generation source when it is determined by the operating state determining means that the driving state is required for highly accurate driving force distribution control. A driving force distribution device using the required radial pressing force value between the first roller and the second roller as a high resolution radial pressing force command value between rollers.

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